1. Field of the Invention
The present invention is in the area of equipment and methods for creating post holes, and pertains more particularly to making square holes of a size for square fence posts.
2. Discussion of the State of the Art
It is well known that there exist at the time of this application a number of alternative tools and methods for digging post holes. A well known tool is the two-handed post-hole spade that has long handles and opposed spades connected at a pivot, such that the spades may be opened by pulling the handle apart and closed by closing the handles. A worker uses both hands to drive the opposed spades into the earth, closes the spades to collect loose earth, and raises the tool out of the developing hole to set the loose earth aside; then repeats the process until the desired depth is attained. It is also well-known that this tool and method is clumsy, tiring, and generally results in a rather large round hole.
Other than hand tools there exists a number of power tools, such as drills and augers of various sorts for making post holes. These are invariably rotary devices that produce round holes, but typically the holes produced by these power tools are more uniform and close to desired size than those produced by hand tools.
Although there are round posts that certainly may be used in round post holes, many people prefer square posts, and for the purpose of this specification four-inch square posts will be considered.
To set a four-by-four post in a post hole, one must produce a round post hole of a diameter great enough to insert the post. For a four-by-four post the diameter needed is the length of the corner-to-corner diagonal of the post, which is 5.67 inches to the nearest one-hundredth of a inch. There needs to be some clearance, so the smallest workable hole diameter is about six inches.
Once one has made a six-inch diameter hole to a desired depth, the post is placed in the hole to the bottom of the hole, leaving relatively large spaces all around the post. Now it is necessary to add loose earth back into the spaces, which are typically rodded to compact the loose soil to better hold the post. This is a difficult process.
What is clearly needed is an apparatus and method for forming a square post hole of very close to the size of the post, with sides that are formed closely compacted in the process, so the post can be driven into the square hole completing the process.